Odd Entries In HTTP Log

All-

I encountered some odd entries in the http log(web filtering) It looks like there may possibly be an issue with one of the servers....

2012:12:31-14:29:40 OASIS httpproxy[29022]: id="0003" severity="info" sys="SecureWeb" sub="http" request="(nil)" function="sc_decrypt" file="scr_scanner.c" line="429" message="EVP_DecryptFinal failed"
2012:12:31-14:29:40 OASIS httpproxy[29022]: id="0003" severity="info" sys="SecureWeb" sub="http" request="(nil)" function="sc_server_cmd" file="scr_scanner.c" line="610" message="ec2-54-252-47-139.ap-southeast-2.compute.amazonaws.com: decrypt failed"

The same entry appears each time the Http proxy checks the servers, every 10 minutes. The ten minute poll time is normal behavior. However the decrypt failed is not. The noted server is pingable with an echo returned.

Thanks,
Jim